KR0148018B1 - Television signal switching system - Google Patents

Abstract

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Description

Tv signal switching system

1 is a block diagram of a prior art switching system.

2A and 2B show partial block diagrams and partial schematic diagrams of preferred embodiments of the present invention.

3A and 3B are display screen diagrams known from the prior art that are useful only to illustrate a situation in which the preferred embodiment described for the present invention has been set.

* Explanation of symbols for main parts of the drawings

100, 200: controller 110: IR receiver

115: remote control device 120: TV tuner

IF: intermediate frequency 125: processing unit

130, 230: Video switch 140, 240: Audio switch

160, 260: video processor 170: display device

180: audio processor 250: PIP device

R231, R232: Resistor D231, D232: Diode

Q231: Transistor

[Field of Invention]

FIELD OF THE INVENTION The present invention relates to the field of television receivers with picture-in-picture functionality.

[Background of invention]

The term television receiver used in the present invention means an apparatus for receiving and processing television signals and includes a television receiver having a display system and a device without a display system such as a video cassette recorder.

The term television monitor / receiver used in the present invention means a television receiver having an RF tuner and a baseband signal input circuit.

Many large format television receivers have a picture-in-picture (also known as fix-in-fix, or PIP) function. In PIPT, video signals from two different sources are combined to form a single image for display on the display screen, where the combined image consists of an important image, an embedded smaller image that is usually located near one of the corners of the display screen. The inserted image is located at one corner of the display screen.

For example, the Sony Video Cassette Recorder (VCR) SLV-70F has a PIP function, in which one signal source must be a video tape in playback mode, and the other signal source is a group consisting of two external video sources and a built-in television tuner. Is selected from. In the above-recognized Sony system, the audio signal selected for playback is the audio signal associated with the picture displayed in the main field of view. If the displayed positions of the video image signals from the two signal sources are exchanged, as the main picture, the currently displayed video and the audio signal sources that are over-aged are automatically selected.

The Sony system uses a three-input audio selector switch with a single control input line. Unfortunately, this requires a trilevel switching signal (ie, including low level, mid level, high level) to be refined to select the appropriate audio signal source. The three-level switching system undesirably requires more complex encoders, more complex decoders, and does not have the original noise cancellation function in two-level digital switching circuits.

Television monitors / receivers with electrically selectable secondary baseband signal inputs are known from RCA CTC-140, manufactured by Thomson Consumer Electric, Indianapolis, Indiana. These monitors / receivers use two-lever digital switching logic to automatically provide appropriate audio when each video source selection is made (ie, tuner, AUX1 or AUX2) rather than using a more complex three-level switching arrangement. do. However, this monitor / receiver does not have a PIP function.

[Summary of invention]

The television receiver has several input video switches and several input audio switches. Each switch has a pair of switching control inputs and each pair is connected together and driven by a system controller. Another controller uses an alternate control signal instead of the control signal that is normally applied to the control input of the audio switch in response to the third control signal generated by the system controller.

[Description of Preferred Embodiment]

In FIG. 1 of the prior art, the controller 100 receives a user-input control signal from the local keyboard 105 and the infrared receiver 110. The IR receiver 110 receives and decodes the remote control signal transmitted by the remote control device 115. Controller 100, which is a microprocessor or microcomputer, causes television tuner 120 to select a particular RF signal in order to be tuned in response to data entered by the user. The tuner 120 generates a signal at an intermediate frequency IF, and includes a first portion 125a having a picture PIX amplifier and a video detector, and a second portion having a voice amplifier, an audio detector, and a stereo decoder. Applies a signal to a processing device 125 comprising 125b). The processing device 125 generates a baseband video signal TV and a baseband left and right audio signal.

The baseband video signal TV is contended via line 126 at one of the four input video switches 130. The baseband left and right audio signals are applied to a pair of inputs to an audio switch 140 that can select a pair of inputs from four pairs of audio inputs. Video switch 130 and audio switch 140 each have three different input stages, called AUX1, AUX2, AUX3, for receiving baseband video and audio signals from an external source, respectively. Each input of video switch 130 and audio switch 140 is selected in response to a binary signal generated by controller 100 and applied to control inputs C ₀ and C ₁ by leads 231 and 232. It is possible. For example, if C ₁ and C ₀ are both at a low signal level (ie, binary; 00), then the TV input is selected. If C ₁ is a low signal level and C ₀ is a high signal level (binary; 01), then AUX1 is selected. If C ₁ is a high signal level and C ₀ is a low signal level (binary; 10), then AUX2 is selected. If C ₁ and C ₀ are both high signal levels (binary; 11), then AUX3 is selected. The selection of corresponding video and audio signals is assured since the control lines 231 and 232 are coupled to the control inputs C ₁ and C ₀ of the video switch 130 and the audio switch 140, respectively.

The selected video signal is applied to the video processor device 160 and eventually displayed on the display screen of the display device 170. The selected audio signal is applied to the audio processor device 180 and eventually played through the speakers 190 and 195. The circuit described above is known from the RCA CTC-140 television receiver manufactured by Thomson Consumer Electric of Indianapolis, Indiana.

Preferred embodiments of the present invention will be described with reference to FIGS. 2A, 2B, 3A, and 3B. 2a and 2b, which perform similar functions in correspondence with FIG.

With reference to FIG. 2A, the picture-in-picture (PIP) device 250 is shown inserted between the video switch 230 and the video processor 260. The A signal input of the PIP device 250 is connected to receive a baseband signal from the built-in tuner / IF circuit of the television receiver, and the B signal input is connected to receive an output signal of the video switch 230. The PIP apparatus 250 has a control input C to which a continuous control service 253 is coupled. A continuous control bus 253 combines the command data from the controller 200 controlling the PIP device 250 to generate a display image, for example, as shown in FIG. 3A of the prior art. The display of FIG. 3A has a main (or first) image 310 and an embedded (or second) image 320. Under a controller command, the PIP function will be enabled and disabled via a continuous bus 253, and the embedded image will be displayed, for example at four corners or some other area. Also under controller commands via a continuous bus 253, the PIP device 250 is adapted to exchange the embedded television image with the primary television image indicated at locations 310 and 320, as shown in FIG. 3b of the prior art. Will be controlled. The voice is preferably reproduced by the speakers 290 and 295 according to the image displayed as the main picture 310 (ie, the associated voice).

However, note that the audio switching of the PIP device 250 of FIG. 1 is not particularly suitable for use in a PIP system inserted between the video switch 130 and the video processor 160 as shown in FIGS. 2A and 2B. do it. In this structure, the audio signal selection should only be based on the video signal selection provided by the video signal switch 230 when the video signal is directed to the main picture display area at the output of the switch 230.

The structure of FIGS. 2A and 2B is in response to a control signal applied to connect the control inputs C ₁ and C ₀ of the video signal switch 230 and the audio signal switch 240 in parallel, or a main picture or insertion. It is provided for the selection of an audio signal in response to a signal indicating whether an image has been exchanged.

In particular, this is achieved by adding resistors R231 and R232, diodes D231 and D232, transistors Q231 and SWAP control line 241. The resistors R231 and R232 are connected to the video switch 250 with the control signal lines 231 and 232 directly connected to the control inputs C ₁ and C ₀ of the video switch 250, as shown in FIG. between each yi byeok control (C _1, and C ₀₎ with each control input of audio switch (C ₁ and C ₀₎ are inserted in series. The anode of diode D231 is coupled to the control input C ₁ connection point of audio switch 240 and resistor R232. The cathodes of the diodes D231 and D232 are connected to the collector of the switching transistor Q231. The emitter of the transistor Q231 is connected to ground and the base is connected to the SWAP terminal of the controller 200 through the current limiting resistor R241. The bubble is shown at the SWAP terminal of the controller 200 of FIG. 2A indicating that the SWAP control signal generated at the output terminal is inverted with respect to the normal logic state. That is, the SWAP control signal applied to the control line 241 indicates a high logic state when the video image is not replaced. The operation of the circuit will now be described.

As noted above, the A input of the PIP device 250 is directly connected to receive a TV video signal from an integrated tuner / IF circuit. The TV audio signal derived from the built-in tuner / IF circuit is selected while the video signal at the input A is directed to the critical picture area and at the input B, the video signal is directed to the embedded (second) display position. You must lose. In this state, the control signal applied to the control line 241 is at a high level, and the A and B input signals of the PIP apparatus 250 are not exchanged. The high level signal A on the control line 241 causes the transistor Q231 to conduct through the diodes D231 and D232 and the resistors R231 and R232, respectively, whereby the signal on the video selection lines 231 and 232 is inverted. Regardless of the level, the code 00 is present at the control inputs C ₁ and C ₀ of the audio switch 240. As noted above, for TV audio selection, the binary code applied on the control inputs C ₁ and C ₀ is 00. If a replacement command is not sent to the PIP device 250 via the series of buses 253, the controller 200 maintains a high logic level on the control line 241. As such, the user enters a command by the keyboard 205 or generates an image displayed in the embedded (second) picture area to be derived from the AUX1, AUX2, AUX3 or TV input, without affecting audio selection. The command will be input by the IR remote controller 215.

When a user enters a SWAP command, it will in turn send a SWAP command to the PIP device 250 by a series of buses 253. This generates the signal at the output of video switch 230 (i.e., at the B input end of the PIP device) to be displayed in the critical picture area, and at the A input end to be displayed in the embedded picture area. Generate a signal. The controller 200 also changes the state of the control signal on the control line 241 to the low signal level. This takes control inputs C ₁ and C ₀ into the audio switch 240 to cause the transistor Q231 to stop conduction and to be controlled by the control lines 231 and 232. In this way, the audio associated with the video signal selected by video switch 230 will be automatically selected for playback when the video signal selected by video switch 230 is displayed in the critical picture area.

2B, resistor 241, transistor Q231, diodes D231 and D232, and resistors R231 and R232 are each replaced by a pair of two input AND gates IC 245a and IC 245b. Lose. Control line 231 is coupled to one input of IC 245a, and control line 232 is coupled to one input of IC 245b. The other input of the AND gate is simultaneously coupled to a terminal labeled SWAP on the controller 200 for receiving a control signal indicating that an important picture and an inserted picture are to be exchanged. The signal improved at the SWAP terminal of the controller 200 is only at a high level when the video signal is exchanged. In this case, the SWAP control signal polarity is opposite to that of FIG. 2A. As such, when the video signals are not exchanged in the a and b of the PIP device 250, the improved signal at the output of IC 245a and IC 245b is forced to a low level, and the control lines 231 and 232 Is replaced at the control inputs C ₁ and C ₀ of the audio switch 240, which is the place of the control signal normally applied. However, when the video signals are exchanged, the control signals on control lines 231 and 232 pass through AND gate ICs 245a and IC 245b. Thus, as selected in FIG. 2B, the audio signal also follows the video signal displayed as the important picture.

The apparatus of FIGS. 2A and 2B allows the use of the same circuit board for use in a best water receiver having a PIP function and a more economical receiver that does not include a PIP function.

Regarding the circuit of FIG. 2A, this is done by removing diodes D231 and D232, transistor Q231, and resistor R240, by replacing PIP device 250 with a jump line from the B hysteresis stage to the output stage, and It is easily implemented during manufacturing by replacing the resistors R231 and R232 with a jump line. With regard to the circuit of FIG. 2B, this is accomplished by replacing AND gates 245a and 245b with jump lines from their respective inputs C ₁ and C ₀ to their respective outputs, and with the jump lines as described above with PIP device 250. Is easily implemented by replacing The dual use of this circuit board saves time and effort, and the cost to be spent in stalking and listing additional circuit boards in the product inventory, and also allows for the use of such switching circuits and controllers, thereby further savings. Enables, considered very important in today's high economic consumer electronics market.

Claims (5)

It has a plurality of video signal inputs (TV, AUX1, AUX2, AUX3) for receiving each baseband video signal, and the first and second control inputs (C ₁ , 2) for receiving respective first and second switching control signals. C ₀ ), and in response to the switching control signal, video switch means 230 having an output terminal for amplifying a video signal selected from the baseband video signal at the plurality of video input terminals, each baseband audio; It has a plurality of signal input terminals (TU, AUX1, AUX2, AUX3) for receiving a signal, and the first and second control inputs (C ₁ , C ₀ ) for receiving each of the first and second control switching signals. And audio switching means 240 having an output terminal for amplifying an audio signal selected from the baseband video signal at the plurality of audio inputs in response to the switching control signal. A baseband television signal switching system comprising control means (200) for generating said first and second switching control signals at respective first and second output stages, said baseband television signal switching system comprising: a second in response to a data signal input by a user; Alternate control over the first and second control signals at the control means 200 for generating a third control signal at an output stage and at the control input of the audio switch means 240 in response to the third control signal. A baseband television signal switching system characterized by additional control means (R231, R232, R241, Q231, D231, D232) coupled to the control means to replace the signal. 2. The first resistor means of claim 1, wherein the additional control means is coupled in series between the first control input terminal of the video switch means and the first control input terminal C ₁ of the audio switch means 240. (R231), second resistance means (R232) coupled in series between the second control input (C ₀ ) of the video switch means and the second control input (C ₀ ) of the audio switch means, and The first control signal is coupled to the connection point of the first control input terminal and the first resistance means of the video switch means, and the second control signal is connected to the second control input terminal and the second resistance means of the video switch means. A baseband television signal switching system characterized in that it is coupled to a connection point. 3. The apparatus of claim 2, wherein the additional control means comprises: a first end coupled to a connection point of the first control input of the first resistance means and the audio switch means and a first coupled to receive the third control signal; A first diode means (D231) having two ends, the second resistor means and the audio switch means are coupled to receive a third control signal and a first end coupled to a connection point of the second control input; A baseband television signal switching system comprising a second diode means (D232) having a second end. 2. The baseband television signal switching system of claim 1, wherein said additional control means comprises an AND gate. 5. The control means according to claim 3 or 4, wherein the control means is used for a television receiver having a picture-in-picture function and the picture-in-picture means interchanges the displayed positions of the first and second video signals. 200) A television receiver, characterized in that said control means converts the logical state of said third control signal when talking.

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